1. What have modern observations shown sunspots to be?

Explanation:

sunspots are areas that appear dark on the sun's surface.They appear dark because they are colder that parts of the sun's surface. However, the temperature of a sunspot is still very high. This can cause a sudden burst of energy space. If a solar flare is very intense, the radiation it releases can interfere with our radio communication here on earth

one person pulls 90n one way and the other has 100n pulling the other way.

so the net force = 90 - 100 = -10n,

or the ans can be 10n if the picture shows -90n and 100n instead.

a skateboard rolling across the street - apex